Ayrton Senna died as the result of an accident on 1 May 1994 while
taking part in the San Marino GP: he lost control of the Williams car he
was driving and hit the wall at the Tamburello. Senna's helmet was
smashed in and the driver died of severe head injuries in the Ospedale
Maggiore a few hours later.
The day before Simtek driver Roland Ratzenberger had died in another
accident (the first fatal accident in F1 for 12 years). Ratzenberger's
death was not deemed to be suspicious by the special prosecutor as the
Simtek driver had damaged the front wing of his car when he had left the
track earlier on and that was judged to be the reason why he had had the
accident.
In the case of Senna's accident the special prosecutor could not find an
obvious reason why an experienced driver such as Senna should lose
control of his car. He also found out that Senna's steering column had
been modified by cutting and welding it just before the race had
started. The special prosecutor decided there was enough evidence to
bring charges of manslaughter against the Williams team. Since at the
time it appeared that the bumps on the Imola track were quite deep and
could have caused enough vibration to damage the welding on the steering
column, charges were brought against the people in charge of the San
Marino racing track as well.
Several people claim that the trial is just an attempt by an unknown
magistrate to become famous using Senna's name. In reality, under Italian
law all accidental deaths must be investigated if there is no obvious
reason as to why the accident has happened.